Chem/Biol 491-Molecules and Medicine- Due 1/6 1:00 PM (tomorrow)
Discussion Questions #1: The placebo effect and drug trials.
Read " Neurobiological Mechanisms of the Placebo Effect "
http://www.jneurosci.org/cgi/content/full/25/45/10390 and "Can the Placebo Be the
Cure?" Martin Enserink in Science (Science 9 April 1999:
Vol. 284. no. 5412, pp. 238 – 240) and
Answer concisely but thoroughly!
1. Define the Placebo Effect. Why is it important for new (and old) drug treatment trials
The positive (generally) brought on by the expectation that a treatment will help. This
effect occurs even if there is no actual therapeutic agent.
Since many treatments involve responses such as pain relief that are susceptible to the
placebo effect, it is important to compare this effect to effect in the presence of actual
drug to decide whether it is biologically effective.
2. What is an active placebo?
A placebo that actually mimics side effects (or even taste) one might feel with a
genuine drug, but has no actual therapeutic effect. That is, an active placebo is more
than just a sugar pill.
3. What does double-blinded mean? Why is it important?
Neither the person giving the drug nor the patient know who is getting genuine drug
versus placebo. This ensures that there are no nonverbal cues are given by the
caregiver to patients receiving real drug or placebo. This could bias the results if a
patient is aware they are getting a placebo (or real drug).
4. Design a protocol for an herbal remedy to take into account the placebo effect.
Patients with headaches receive a pill containing the feverfew herb or inactive starch.
The pills are coded so that neither the doctor nor the patient (only the study leader)
knows which is which. Patients are then interviewed to determine whether their
headaches have improved.
1. Headaches may be due to different causes (migraine vs. tension). A large group
would be needed to ensure equal representation. This could be a problem.
2. The herb pill could smell or taste or look different (or produce an aftertaste). This
could bias expectations.
3. Many other possible problems
5. Design a FLAWED protocol and explain why.
Patients with headaches receive a pill containing the feverfew herb. Patients are then
interviewed to determine whether their headaches have improved.
This protocol has no control and both patient and caregiver know they are giving or
receiving drug. This enhances placebo effect and makes it impossible to determine
whether any benefit beyond placebo has occurred.
6. Criticize AND then defend the following statement: " It doesn't really matter whether
there is a pharmacological or scientific basis for a treatment if a large portion of
patients feel better."
7. Can you think of situations when a placebo control should not be done? How could
you be sure the treatment worked in that case?
Something like heart surgery in which a placebo (fake surgery) could be dangerous
would be such a situation. To determine whether it worked you would have to find
some chemically or physically defined endpoint (i.e. increased blood flow to heart) that
could be measured. Even so it would be difficult in some cases to prove effectiveness.
Another scenario is when a response is overwhelmingly positive (like, e.g. , tumor
regression in all patients receiving drug). At this point it would be unethical to continue
giving other cancer patients a placebo.